The most famous case of the Affair…

The most famous case of the Affair of the Poisons is Catherine Deshayes Monvoisin or La Voisin, who implicates a number of important individuals in the French court.

Promiscuous throughout her marriage to her husband, an unsuccessful jeweler named Monvoisin, she had practiced chiromancy and face-reading to retrieve her and her husband's fortunes, and had gradually added the practice of witchcraft, in which she had the help of a renegade priest, Etienne Guibourg, whose part was the celebration of the "black mass", a parody of the Christian Mass.

She practices medicine, especially midwifery, procures abortion, and provides love powders and poisons.

Her chief accomplice is one of her lovers, the magician Lesage, whose real name is Adam Cœuret.

The great ladies of Paris had flocked to La Voisin, who has accumulated enormous wealth from them.

Among her clients are Olympe Mancini, Comtesse de Soissons, who had sought the death of the king's mistress, Louise de La Vallière; and the Comtesse de Gramont ("la belle Hamilton"), among others.

Françoise-Athénaïs, marquise de Montespan, is accused of working with La Voisin to poison Louis XIV and Mademoiselle de Fontanges, a woman who is sleeping with Louis.

Although La Voisin never admits to working with Montespan, many other people claim she had worked with La Voisin but there is no sufficient evidence of this and many of the confessor's stories are inconsistent.

Also involved in the scandal is Eustache Dauger de Cavoye, the eldest living son of a prominent noble family.

De Cavoye had been disinherited by his family when, in an act of debauchery, he chose to celebrate Good Friday with a black mass.

Upon being disinherited he had opened a lucrative trade in "inheritance powders" and aphrodisiacs.

He mysteriously disappears after the abrupt ending to Louis's official investigation in 1678.